Air regulating means for liquid fuel furnaces



April 9, 1935.

H. C. GRANT, JR

AIR REGULATING MEANS FOR LIQUID FUEL FURNACES FIGURE I Filed July 1, 1932 2 Sheets-Sheet 1 36 c \o I 0 7 F. L 32 371 I? l 4 39} 2s 18 w q '13 z s 7 72 t 2 4 68 775 H32 D "H a 74 69 76 7' I 3.4 l o INVENTOR HARRY CAA/IPBELL GRANT, JR.

ATTORNEY April 1935- H. c. GRANT, JR 1,997,558

AIR REGULATING MEANS FOR LIQUID FUEL FURNACES Filed July 1, 1932 2 sheets-sheet? FIGURE 2 o FIGURE 3 INVENTOR HARRY CAMPBELL GkA/w J/z ATTORNEY Patented Apr. 9, 1935 UNITED STATES PATENT OFFICE AIR REGULATING MEANS FOR LIQUID FUEL FURNACES .Harry Campbell Grant, In, New York, N. Y., as-

signor to Walter Kidde & Company, Inc., New York, N. Y., a corporation of New York Application July '1, 1932; Serial No. 620,429

Claims.

pcrtionate quantities of .fuel and air are introduced into a furnace under all variations of heat production found desirable.

More specifically, the present invention constitutes an improvement in, or rather a desirable modification of, the invention shown and described in my co-pending application for Letters Patent of the United States, Serial No.'620,- 430, filed 'on even date herewith.

In common with my herein referred to copending application, wherein a balancing mechanism controlled by the variable pressures of fuel and air is employed to control the supply of steam to the air delivery control means of a furnace, whereby to maintain a proper balance between the quantities of fuel and air delivered to the furnace, the present invention preferably contemplates the use of electrically operated means for translating the controlling effect of the balancing mechanism into control of the supply of steam to the air delivery control means.

In somewhatmore specific terms the use of an electrically controlled motor driven valve for controlling the supply of steam to a blower engine, is contemplated, whereby to secure automatic' adjustment of the forced draft of a furnace.

With such an arrangement, when some condition' arises making necessary a readjustment of the forced draft, the motor driven blower valve must open or close a certain amount to re-establish a proper forced draft. In view of the fact that the fine adjustment to be made requires the use of a slow-adjusting blower valve, and in order to reduce the time necessary for the motor driven blower valve to open or close the required amount, whereby to more closely appreach the desired continuous balanced condition between the quantities of fuel and air, the present invention provides, specifically, a small by-pass electro-magnetically operated valve which, when it is necessary to open the motor driven blower valve wider, opens full and gives a sudden small increase in steam to accelerate the blower more quickly, the motor driven valve continuing to open slowly to obtain a close adjustment on the forced draft. Conversely, when the motor driven valve starts to close, the electro-magnetic valve closes completely to reduce the speed of the blower more quickly, the motor driven valve giving the final close adjustment.

It is accordingly an object of the present invention to provide, in an apparatus of the nature referred to, means to anticipate requisite increases and decreasesin the quantity of actuating fluid, such'as steam, supplied to the air delivery control means of a furnace.

A feature of the invention is the provision, in one specific embodiment thereof, of an electromagnetically operated by-pass valve operating in conjunction with an electrically operated main blower valve.

It is a further object of the invention to provide, in connection with the feature just referred to, means to open or-close the by-pass valves quickly and in advance of requisite degrees of opening and-closing of the main valve, but subsequent to the initiation of opening and closing movements of the main valve.

These and further objects of the invention will be apparent as the same is described more fully in connection with the accompanying drawings wherein:

, Figure 1 is a combined diagrammatic representation and wiring diagram of one embodiment of my invention.

Figure 2 is a somewhat enlarged view of an electro-magnetically operated by-pass valve capable of use with the present invention.

Figure 3 is a somewhat enlarged view of the means for controlling the electrd-magnetically operated by-pass valve.

Referring to Figure 1, I have illustrated at A a furnace having an induced draft stack B and an air delivery duct C, the delivery of air to the latter being effected by a blower D controlled by a prime mover E in turn subject to the controlling effect of a steam supply valve F.

The reference character. G represents a source of steam, while H represents the fuel supply to the furnace A.

The valve I is specifically concerned with the present invention and will be referred to in detail further on in this description.

At I is shown a balance arm having a fulcrum at 2 and having suspended therefrom two air containers 3 and 4/ These air. containers are arranged to rise and fall within tanks 5 and 6 containing an air-sealing liquid, such as water. The interior of the air container 3 is connected by means of a pipe line I with the forced draft duct C, while' the interior of the air container 4 is connected bymeans of a pipe line B with the induced draft stack B. At 9 is shown an expansible bellows-like member which is connected by a pipe line l3 with the fuel supply H and which is adapted to expand and contract upon variations in the pressure of the fuel, the movements of the bellows-like member being transmitted, against the compressive force of a spring H, to an arm l2, pivoted at l3, and connected by a link with a carriage 16 supporting a number of weights l6 and adapted to be moved along the balance arm I with the aid of a roller 11.

The reference numeral l3 represents a contact supported on the balance arm I and adapted to rise and fall with the balance arm between contacts I3 and 23 arranged to define upper and lower limiting positions of the balance arm. The contact 13 is electrically connected, as by a flexible connection 21, wires 22, 23, 2| and 26, fuse 26, and one side of the double pole switch 21 to the positive side of a source of electrical energy. The upper contact 13 is connected by wire 23, through the coil of an electro-magnet 23' with one side of an electric limit switch assembly generally indicated as K, which will be more particularly described hereinafter. The limit switch is in turn connected with the negative side of the source of electrical energy through wires 33, 3| and 32, fuse 33, and one side of the double pole switch 21. The lower contact 23 is connected through the coil of the electro-magnet 34' and wire 35 to the opposite side of the limit switch K and thus is similarly connected to the negative side of the source of electrical energy by wires 33, 3| and 32, fuse 33 and the negative side of the double pole switch 21.

The limit switch K consists of a base 3| of insulating material having conducting pieces 32' and 33 pivoted thereon. The conducting pieces 32' and 33' are respectively electrically connected to the electrical leads 35 and 23. Mounted on the base 3|, between the conducting pieces 32' and 33, and having electrical contacts 36' and 31, is a conducting piece 36' which is electrically connected to the lead 33. The conducting pieces 32' and 33' make contact respectively with contacts 36' and 31'. The conducting piece 32' is held against contact 36' by a springpressed button assembly 33' mounted in the base 3 I and likewise the conducting piece 33' is held against the contact 31' by the pushbutton 33.

The operation of the limit switch assembly is eifected by means of a slide block 66' provided with motion transmitting screw threads engaging with co-operating screw threads on the valve stem 31. The slide block 43' is provided with a depending projection 4| lying between the conducting pieces 32' and 33'. The slide block 66' is grooved as at 62' for the reception of bars 63' which are supported by the uprights 64'. By reason of this arrangement of parts; rotation of the valve stem 31 will cause the slide block 46' to slide along the bars 3' and will cause the projection ll to engage either the conducting piece 32 or the conducting piece 33, breaking the contact at either 36 or 31, depending upon the direction of rotation of the shaft 31.

The various parts of the limit switch assembly are so proportioned that, when the steam supply valve F is completely closed, the limit switch toward the valve F, i. e., the conducting piece 33', opens the contact 31', thus opening the energizing circuit of the electro-magnet 23' and preventing the valve from attempting to close further. Conversely, the limit switch towards motor 36, i. e., the conducting piece 32', when engaged by the slide block to open the contact 36, opens the energizing circuit of the electro magnet 34' and prevents the valve from opening further.

In practice, the electro-magnets 23' and 34' are arranged on a single support and control a single armature pivoted intermediate of the electro-magnets and extending over the cores 'of both electro-magnets, as is described in my copending application Serial No. 620,430. For the present it will be sufllcient to note that the energization of the electro-magnet 34 eil'ects the making of contact at 63 and 63, while the energlzation of the electro-magnet 23' eil'ects the making of contact at 13 and 1|, the movable contact elements 12, 13, 14 and 15 being mounted on but electrically insulated from the armature. It will, of course, be noted that the movable contacts 12 and 13 are electrically connected, while the movable contacts 16 and 15 are similarly electrically connected.

The fixed contacts 66, 63, 10 and 1| are mounted in any suitable manner and between the contacts 63 and 10 is connected a resistance 16,

while between the contacts 68 and 1| is connected a resistance 11. A switch 18 is arranged to short-circuit the resistance 11 when desired.

The resistances 16 and 11 are, when there is a closed electrical circuit through them, in circuits which control the blower steam supply valve F. The resistance 11 is in the circuit which controls the opening of the valve and, therefore, when it is desired to open this valve rapidly, the resistance 11 should be short-circuited by closing the switch 13. Lamps 13 and are provided to indicate whether the valve F is being opened or I closed.

An electrical motor 36 is arranged to rotate the valve stem 31 in either direction through the reduction gear assembly 38, the armature leads for the motor being shown at A1 and A2, while the field leads are shown at P1 and F2, the latter being connected respectively to the positive and negative sides of the source of electrical energy by wires 33, 24 and 25, and by wires 46. 4|, 3i and 32 respectively.

In view of the fact that the apparatus as just described has been disclosed in my herein referred to co-pending application, in which its operation has been described in full, it is believed to be sufficient to point out, in so far as the present invention is concerned, that closing of the contact lL-26 eil'ects energization of the armature of the motor 36, causing it to rotate the valve stem 31 in such a direction as to open the valve F to increase the supply of steam to the prime mover E and consequently increase the quantity and pressure of the air delivered to the furnace by the blower D, while closing of the contact 13-" effects energization of the armature of the motor 36 with a reversed polarity, causing it to rotate the valve stem 31 in such a direction as to close the valve F to decrease the supply of steam to the prime mover E and consequently decrease the quantity and pressure of the air delivered to the furnace by the blower D.

As a matter of interest, it should be noted that the contacts "-26 will close to increase the forced draft upon a decrease in the induced draft. or upon a drop in the steam pressure (causing the blower to slow down). or upon an inm in the pressure of the fuel, or upon a. decrease in the forced draft itself, due to the cutting in of more fires. Conversely, the upper contact Ill -I3 will close to decrease the forced draft upon an increase in the induced draft. or upon an increase in the steam pressure, or upon a decrease in the pressure of the fuel, or upon an increase in the forced draft itself, due to the cutting out of fires.

It will therefore be seen that the arrangement just described enables a balanced condition to be maintained between the variable pressures of the fuel and air delivered to a furnace, and hence a properbalance is effected between the quantitles of fuel and air delivered to the furnace.

With such an arrangement, when some condition arises making necessary a readjustment of the forced draft, the motor driven blower valve F must open or close a certain amount to re-establish a proper'forced draft. In view of the fact that the adjustment to be made is rather fine, the blower valve F is necessarily slow-adjusting, and in order to reduce the time necessary for the motor driven valve F to open or close the required amount, so as to more closely approach the desired continuous balanced condition between the quantities of fuel and air delivered, I provide a small by-pass electro-magnetically operated valve I which, when it is necessary to open the motor driven valve F wider, opens full and gives a sudden small "increase insteam to accelerate the blower D more quickly, the motor driven valve F continuing to open slowly to obtain a close adjustment on the forced draft. Conversely, when the motor driven valve starts to close, the electro-magnetic valve I closes completely to reduce the speed of the blower more quickly, the motor driven valve giving the final close adjustment.

The manner of operation of the valve I can best be understood in connection with Figure 2 in which it is more clearly shown than in Figure 1. The valve I and its operating electro magnet L are both commercially obtainable, so that it is unnecessary to show and describe them in detail herein. The valve I is'shown as a simple poppet valve normally maintained in its closed position by a coiled spring and opened by depression of the valve stem 42. The electro-magnet. L is shown with a base 43 on which are mounted standards 44 and 45 on which in turn are pivoted levers 46 and 41. One end of the lever 41 is pivoted on an extension on one end of the core 48 of the electro-magnet L, while its other end is The manner in which the electro-magnet L is energized and deenergized will now be described in connection with Figure 3, reference being had, however, to Figure 1 also. In Figure 3 the reference numeral 53 represents the shaft of an element of the reduction gear assembly 38, said element being an intermediate element and hence having a rotative speed less than the inputspeed from the motor 36 but greater than the output speed. to the valve stem 31, whereby the shaft 53 can be employed to eifect an operation subsequent to the initiation of the operation of the motor 36, but in advance of the completion of the opening or closing movement of the valve stem 31. On the shaft 53 is mounted a disc 54 having notches 55 and adapted to rotate with the shaft. Mounted below the disc 54 and on a base 56 is a standard 51 on'which a rocker arm 58 is pivoted at 59. The standard 51 also supports a single pole single throw toggle switch 60 having electrical leads 5! and 52. The toggle switch 60 has the usual tiltable lever 43, and the toggle switch is so disposed that the head of the lever 63 lies.

the rocker arm 58 to leave the notch 55 and to ride upon the periphery of the disc, whereby the rocker arm 58 will carry with it the tiltable lever 63 of the toggle switch, thus operating the latter. So long as the disc 54 rotates in the same direction, or even stops, the rocker arm 58 will rest on the periphery of the disc, as only rotation in'the reverse direction will enable the rocker arm to engage one of the notches 55. If, now, the direction of rotation of the disc 54 is reversed, the spring 65 returns the rocker arm momentarily to its normal position, from which it is immediately rocked to its opposite position when the upper end of the rocker arm is expelled from the notch and caused to ride upon the pcriphery of the disc, thus causing the toggle switch to be operated oppositely to its initial operation.

With the foregoing construction in mind, ref-- erence should now be made to Figure 1, in which it will be seen that an initially open circuit exists from the positive side of the source of electrical energy, through one side of 'the double pole switch 21, fuse 25, wires 25 and 66, electro-masnet L, wire, 61, lead 62, normally open switch 60, lead 5|, wires 68, 4|, II and 32, fuse 33, and the other side of the double pole switch 21 to the negative side of the source of electrical energy.

It will of course be understood that the normally open switch 60 and the rotatable disc 54 are so mounted that the switch will be closed when the forced draft must be increased, and will be opened when the forced draft must be decreased. With this in mind it will be apparent that the initiation of the rotation of the motor 38 in a direction to open the blower valve F to effect a desired increase in the forced draft, ,will resuit in energization of the electro-magnet L.

This will cause full opening of the valve I which will give a sudden small increase in the supply of steam to the blower engine, whereby the blower D will be more quickly accelerated, the

valve F continuing to open slowly to obtain a closer adjustment. If, now, the motor driven valve starts to close, the electro-magnetic valve I closes completely to reduce the speed of the blower more quickly, the motor driven valve giving the final close adjustment.

From the foregoing description it. will be apparent that I have made a desirable improvement in regulating mechanisms of the type referred to and it is to be understood that the present invention, while it has been described with specific reference to the accompanying drawings, is not to be limited, save as defined in the appended claims.

- I claim: 1. In a regulating mechanism for maintaining a balanced condition between the quantities of fuel and air delivered to a furnace and embodying a beam balanced about a fulcrum by the variable pressures of the fuel and the air, air delivery means for delivering air to a furnace, a steam actuated prime mover for actuating the air delivery means, means to control the supply of steam to the prime mover, and means to control the last named means by movement of the beam on either side of its balanced position, said steam supply control means being operable for eilecting both increases and decreases in the quantity of steam supplied to the prime mover and having a relatively slow-adjusting controlling eifect, the combination of means to anticipate the requisite increases and decreases in the. quantity of steam supplied to the prime mover, said last named means comprising auxiliary means acting relatively quickly to initiate or terminate an auxiliary flow of steam to the prime mover, and means actuated upon movement of the beam to operate the auxiliary means.

2. In a regulating mechanism for maintaining a balanced condition between the quantities of fuel and air delivered to a furnace and embodying a beam balanced about a fulcrum by the variable pressures of the fuel and the air, air delivery means for delivering air to a furnace, a steam actuated prime mover for actuating the air delivery means, a main valve for controlling the supply of steam to the prime mover, and means to control the main valve by actuation of the beam on either side of its balanced position, said main valve being operable for effecting both increases and decreases in the quantity of steam delivered to the prime mover and having a relatively slow-adjusting controlling effect, the combination of means to'anti'cipate requisite increases and decreases in the quantity of steam supplied by the main valve to the prime mover, said last named meanscomprising an auxiliary valve having a lesser steam controlling eflect than the main valve but acting relatively quickly to initiate or terminate an auxiliary flow of steam to-the prime mover, and means to operate the auxiliary valve actuated subsequent to and as the result of the initiation of the operation of the means controlled by movement of the beam for controlling the main valve.

3. In a regulating mechanism for maintaining a balanced condition between the quantities of fuel and air delivered to a furnace and embodying a beam balanced about a fulcrum by the variable pressures of the fuel and the air, said beam air delivery means, a main valve for controlling the supply of fluid to the prime mover and having a relatively slow-adjusting controlling effect, electrically operated rotary means connected to the main valve for effecting different degrees of opening and closing of the valve; said electrically operated rotary means having a relatively high rotative speed and being adapted to rotate in either direction, speed reducing means in the connection between the valve and the electrically operated rotary means and having at least one speed intermediate the input speed to the speed reducing means and the output speed from the speed reducing means, an electrical circuit for controlling the rotary means to cause it to effect an opening movement of the main valve, a secnd electrical circuit for controlling the rotary means to cause it to effect a closing movement of the main valve, two electrical contacts arranged to deflne upper and lower limiting positions of the beam, each contact being electrically connected with a different one of the two electrical circuits, and a contact on the beam arranged to float normally between the first mentioned contacts and adapted to effect energization of either one or the other of the two electrical cir cuits upon contacting with either one or the other of the flrst mentioned contacts, the combination of means to anticipate requisite opening and closing movements of the main valve, said last named means comprising an auxiliary valve having a lesser fluid controlling effect than the main valve but acting relatively quickly to initiate or terminate an auxiliary flow of fluid to the prime mover, and means to operate the auxiliary valve actuated upon the initiation of the operation of the speed reducing means and from an intermediate speed element of said speed reducing means.

4. In a regulating means for controlling a mechanism to be operated at varying speeds by the delivery of a fluid from a source of supply and embodying a valve for controlling the supply of the fluid to the mechanism, electrically operated rotary means connected to the valve for effecting different degrees of opening and closing of the valve, said electrically operated rotary means having a relatively high rotative speed and being adapted to rotate in either direction subject to the controlling effect of a selective controlling means, and speed reducing means in the connection between the valve and the electrically operated rotary means whereby said valve has a relatively slow-adjusting controlling effect, the combination of means to anticipate the requisite opening and closing of the valve under the influence of the selective controlling means, said last named means comprising an auxiliary valve having a lesser fluid controlling eifect than said valve but acting relatively quickly to initiate or terminate an auxiliary flow of fluid to said mechanism, said auxiliary valve being adapted for electro-magnetic operation, and an electrical circuit for eflecting operation of the auxiliary valve and including a contact actuated subsequent to and as the result of the initiation of the aforesaid electrically operated rotary means under the control of the aforesaid selective controlling means.

5. In a regulating mechanism for maintaining a balanced condition between the quantities of fuel and air delivered to a furnace and embodying a beam balanced about a fulcrum by the variable pressures of the fuel and the air, air delivery means for delivering air to a furnace, a fluid actuated prime mover for actuating the air delivery means, a main valve for controlling the supply of fluid to the prime mover and having a relatively slow-adjusting controlling effect, electrically operated means for effecting difierent degrees of opening and closing of the main valve,

an electrical circuit for controlling the electricallyoperated means to. cause it to effect an opening movement of the main valve, a second electrical circuit for controlling the electrically operated means to cause it to eifect a closing movement of the main valve, two electrical contacts arranged to deflne upper and lower limiting positions of the beam, each contactbeing electrically connected with a different one of the two electrical circuits, and a contact on the beam arranged to float normally between the first mentional contacts and adapted to effect energization of either one or the other of the two electrical circuits upon contacting with either one or the other of the first mentioned contacts, the combination of means to anticipate requisite 4 opening and closing movements of the main valve, said last named means comprising an auxiliary valve having a lesser fluid controlling elf-- iect than the main valve but acting relatively quickly to initiate or terminate an auxiliary flow of'fiuid to the prime mover,- and means to operate the auxiliary valve actuated subsequent to and as the result of the initiation of the operation of the electrically operated means for effecting different degrees of opening and closing of the main valve.

HARRY CAMPBELL GRANT,. JR. 

